fertiliser Flashcards
soil fertility
ability of the soil to give plants enough nutrients to grow
fertilizer
substances added to the soil to provide nutrients
importance of fertilizers
-they increase nutrients in the soil needed by plants to grow well
- they increase crop yields
-improve the quality of the produce
-improve soil structure
-add any nutrients that the soil may not have had before
examples of organic fertilizers
-green manure
-farm yard manure
-compost manure
-crop residues
GREEN MANURE
is made from crops that have been ploughed back into the soil while they are still green or at flowering stage such as beans , peas , groundnuts , peas, lucerne
GREEN MANURE IS A GOOD SOURCE OF NITROGEN AND PHOSPHORUS
FARM YARD MANURE( several sources )
-kraal manure from cattle, goats, sheep and pigs
-stable manure from horses
-chicken manure from chickens
IT CONTAINS A LARGE AMOUNT OF NUTRIENTS ESPECIALLY NITROGEN,PHOSPHORUS AND POTASSIUM
COMPOST MANURE
from remains of animals and plants that have been decomposed by bacteria and fungi
CROP RESIDUES
leftovers, parts of crop like stalks that were not harvested can be ploughed back into the soil where they decompose and return plant nutrients to the soil
advantages of organic fertilizers
-they are easy to obtain and are cheap
-they improve soil structure
-they don’t burn or cause damage to crops when they come in contact with them
-they are environmentally friendly
-they promote the activity of micro organisms
- they release nutrients and elements into the soil slowly. this means the nutrients are available to the plants over a long period of time
disadvantages of organic
take a long time to decompose and be ready for use
-they are less concentrated
-they are applied in large quantities in order to increase soil fertility
-the exact amount of plant nutrients elements within the organic is not known
inorganic fertilizer are divided into 2 main groups
straight(single) fertilizer
compound fertilizer
straight fertilizer
provide only one element of nutrients to the soil
Nitrogenous fertilizer:
urea
LAN
ammonium nitrate
Phosphate fertilizer:
-single super phosphate
-double superphosphate
-triple superphosphate
Potassium fertilizer
-muriate of potash
-potassium nitrate
-potassium sulphate
compound fertilizer
these are inorganic fertilizers that contain two or more elements/nutrients e.g 2:3:2
advantages of inorganic fertilizer
-saves time and labour as they do not have to be collected
-they can be added in the correct amount needed by a particular crop
- they are easy to handle and store since they are brought in bags
-they are quick to dissolve
-needed in smaller amounts cause they are concentrated
-can be stored for longer periods without losing nutrients
disadvantages of inorganic
-very expensive
-they can burn or damage plants when in contact with them
-can pollute the environment like rivers and dams
-do not improve soil structure
-requires technical skills
Basal dressing
when fertilizer is applied before planting
Top dressing
when fertilizer is added into the soil after the plants have emerged
Fertilizer application methods
Broadcasting
-Banding
-Drilling
-Side dressing
-Fertigation
-Foliar application
Broadcasting
when fertilizers are sprinkled over the surface and then mixed with soil before seeds are planted
Drilling
this is when both seeds and fertilizers are placed in shallow furrows or drill
Banding
placing the fertilizer in bands or strips below the soil surface at planting time
Side dressing
applying fertilizers along rows after the plants have emerged above the soil
Fertigation
applying fertilizer with water and then apply the mixture to the soil
Foliar application
the fertilizer is dissolved in water and then sprayed on the leaves of the plants
major elements
nutrients required by plants in large quantities MACRO ELEMENT
minor elements
nutrients required by plants in small quantities MICRO ELEMENT
Major elements found in fertilizers
*nitrogen(N)
*phosphorus(P)
*potassium(K)
how nutrients can be lost in soil
-leaching
-soil erosion
-volatilization
-denitrification
-incorrect soil pH
-removal of crops and crop residues
-continuous cropping
-burning the veld
leaching
when nutrients dissolve in water and carried deep down the ground where plants cannot use them
volatilization
the process by which something evaporates and turns into gas
